Hydropower is a large renewable energy contributor to the global production of electricity. Unfortunately, though, there are many small, low-head sites that do not have any power generation equipment generating power from water flowing through the site. A reason for this is the value of the power to be generated at these sites is not enough to justify the cost to design and install a power generation system specifically for that particular site. Because these sites are small and the available water has a low head, typically thirty feet or less, the amount of power that can be generated is low compared to large hydro-electric dams. And, the cost to design and install a power generation system is typically high because most power generation systems are specifically designed for the specific conditions of the water flow including its total head (vertical drop) experienced at the specific site. Most hydro turbines operate at a constant speed that is dictated by the generator and desired frequency of the AC power to be generated. Because each site has a unique set of flow conditions, each turbine and generator set is specifically designed to operate in the unique flow and head conditions of the specific site. Adding to the high cost is the reality that many of the small, low-head dams or natural drops do not have the civil works—particularly an intake—that would allow one to easily add a penstock, turbine and generator set to the water that flows over the dam. To add a power generation system to these sites one would also have to do significant work to the existing dam structure to enable the water to enter the power generation system. The work to build an intake is particularly high-risk and expensive. So, often it doesn't make economic sense to design and install a unique power generation system for a site that can't produce a large amount of power.
Thus, there is a need for a power generation system that can efficiently extract energy from a variety of different flow characteristics in a liquid so that a single system may be used to generate power from a variety of different sites, and a single system may be used to generate power from a single site having a variety of different flow characteristics. There is also a need for a system that is easily installed with minimal civil works, self-cleaning or has an easily cleaned intake; has reduced operation and maintenance requirements and uses power electronics.